Liquid metal micro-switches (LIMMS) have been developed to provide reliable switching capability using compact hardware (e.g., on the order of microns). The small size of LIMMS make them ideal for use in hybrid circuits and other applications where smaller sizes are desirable. Besides their smaller size, advantages of LIMMS over more conventional switching technologies include reliability, the elimination of mechanical fatigue, lower contact resistance, and the ability to switch relatively high power (e.g., about 100 milli-Watts) without overheating, to name just a few.
According to one design, LIMMS have a main channel partially filled with a liquid metal. The liquid metal may serve as the conductive switching element. Drive elements provided adjacent the main channel move the liquid metal through the main channel, actuating the switching function.
During assembly, the volume of liquid metal must be accurately measured and delivered into the main channel. Failure to accurately measure and/or deliver the proper volume of liquid metal into the main channel could cause the LIMM to fail or malfunction. For example, too much liquid metal in the main channel could cause a short. Not enough liquid metal in the main channel may prevent the switch from making a good connection.
The compact size of LIMMS makes it especially difficult to accurately measure and deliver the liquid metal into the main channel. Even variations in the tolerance of the machinery used to deliver the liquid metal may introduce error during the delivery process. Variations in the dimensions of the main channel itself may also introduce volumetric error.
An embodiment of the invention is a switch comprising a channel plate having a main channel and at least one waste chamber formed therein. The switch may also comprise a substrate having at least one contact pad. A liquid switching element is deposited on the at least one contact pad. A portion of the liquid switching element is isolated from the main channel into the at least one waste chamber when the channel plate is assembled to the substrate.
Another embodiment of the invention is a method for assembling a switch, comprising the steps of: depositing a liquid switching element on a substrate; positioning a channel plate adjacent the substrate; moving the channel plate toward the substrate; isolating a portion of the liquid switching element from a main channel in the channel plate into a waste chamber in the channel plate.
Yet other embodiments are also disclosed.